The present invention relates to a jet engine thrust reverser system and, more particularly, to a thrust reverser system that includes actuators having an automatic relock and lock drop prevention mechanism.
When jet-powered aircraft land, the landing gear brakes and imposed aerodynamic drag loads (e.g., flaps, spoilers, etc.) of the aircraft may not be sufficient to slow the aircraft down in the required amount of runway distance. Thus, jet engines on most aircraft include thrust reversers to enhance the stopping power of the aircraft. When deployed, thrust reversers redirect the rearward thrust of the jet engine to a forward direction to decelerate the aircraft. Because the jet thrust is directed forward, the jet thrust also slows down the aircraft upon landing.
Various thrust reverser designs are commonly known, and the particular design utilized depends, at least in part, on the engine manufacturer, the engine configuration, and the propulsion technology being used. Thrust reverser designs used most prominently with turbofan jet engines fall into three general categories: (1) cascade-type thrust reversers; (2) target-type thrust reversers; and (3) pivot door thrust reversers. Each of these designs employs a different type of moveable thrust reverser component to change the direction of the jet thrust.
Cascade-type thrust reversers are normally used on high-bypass ratio jet engines. This type of thrust reverser is located on the circumference of the engine""s midsection and, when deployed, exposes and redirects air flow through a plurality of cascade vanes. The moveable thrust reverser components in the cascade design includes several translating sleeves or cowls (xe2x80x9ctranscowlsxe2x80x9d) that are deployed to expose the cascade vanes.
Target-type reversers, also referred to as clamshell reversers, are typically used with low-bypass ratio jet engines. Target-type thrust reversers use two doors as the moveable thrust reverser components to block the entire jet thrust coming from the rear of the engine. These doors are mounted on the aft portion of the engine and may form the rear part of the engine nacelle.
Pivot door thrust reversers may utilize four doors on the engine nacelle as the moveable thrust reverser components. In the deployed position, these doors extend outwardly from the nacelle to redirect the jet thrust.
The primary use of thrust reversers is, as noted above, to enhance the stopping power of the aircraft, thereby shortening the stopping distance during landing. Hence, thrust reversers are primarily deployed during the landing process to slow the aircraft. Thereafter, when the thrust reversers are no longer needed, they are returned to their original, or stowed, position and are locked.
The thrust reversers in each of the above-described designs are moved between the stowed and deployed positions by means of actuators. One or more of these actuators may include a locking device to prevent unintended thrust reverser movement. Current thrust reverser systems incorporate the locking devices as separate units that may attach to one or more components of the thrust reverser system. For example, U.S. Pat. No. 4,586,329 (the ""329 patent) discloses a locking device that is coupled to the gear shafts that couple the thrust reverser system actuators together. In another example, U.S. Pat. No. 5,448,884 (the ""884 patent) discloses a locking device that is attached to a thrust reverser actuator. While these locking devices are generally safe, they tend to be complex and heavy for certain applications, and have a system inertia and size envelope that is not compatible with certain applications. In addition, neither of these patents discloses automatically moving the locking devices to a locked position when the actuator is moved to the stowed position, nor the inhibition of actuator locking when the actuator is unlocked and it is not in the stowed position. Drawbacks also can be associated with the power sources for these locks.
Hence, there is a need for a thrust reverser actuator locking device that improves upon one or more of the above-noted drawbacks. Namely, a locking device that is not complex or heavy as compared to known locks, and/or does not significantly increase actuator system size and/or weight, and/or automatically relocks the actuator upon thrust reverser stowage, and/or inhibits actuator locking when it is unlocked and is not in the stowed position. The present invention satisfies one or more of these needs.
The present invention relates to a system for moving thrust reversers that includes a plurality of actuators each having an integrated locking mechanism that prevents unintended actuator movement, and thus unintended thrust reverser movement, that automatically relocks the actuator upon stowage, and that inhibits unintentional locking until the thrust reverser is stowed.
In one embodiment, and by way of example only, a system for moving a thrust reverser includes at least one power source, at least two drive mechanisms, and at least two actuator assemblies. Each actuator assembly is coupled to at least one of the drive mechanisms and is operable to move, upon receipt of the driving force, between a stowed position and a deployed position. At least one of the actuator assemblies includes a housing, a drive shaft, an actuator, a lock assembly, and a lock inhibitor assembly. The drive shaft is rotationally mounted within the housing, and has a gear portion, a lock portion, and a first end adapted to couple to at least one of the drive mechanisms. The actuator extends from the housing and has a drive gear mounted to engage the gear portion of the drive shaft. The lock assembly is movably mounted on the housing and is selectively operable to move between a locked and an unlocked position, whereby the lock assembly engages and disengages the drive shaft lock portion in the locked and unlocked position, respectively, to thereby prevent and allow rotation thereof, respectively. The lock inhibitor assembly is mounted on the housing and is selectively operable to move between an engaged and a disengaged position, whereby the lock inhibitor engages the lock assembly in the engaged position to thereby prevent movement thereof to the locked position.
In another exemplary embodiment, a thrust reverser actuator with an integrated lock for use in a system having at least one drive mechanism for moving a thrust reverser between deployed and stowed positions includes a housing, a drive shaft, an actuator, a lock assembly, and a lock inhibitor assembly. The drive shaft is rotationally mounted within the housing, and has a gear portion, a lock portion, and a first end adapted to couple to at least one of the drive mechanisms. The actuator extends from the housing and has a drive gear mounted to engage the gear portion of the drive shaft. The lock assembly is movably mounted on the housing and is selectively operable to move between a locked and an unlocked position, whereby the lock assembly engages and disengages the drive shaft lock portion in the locked and unlocked position, respectively, to thereby prevent and allow rotation thereof, respectively. The lock inhibitor assembly is mounted on the housing and is selectively operable to move between an engaged and a disengaged position, whereby the lock inhibitor engages the lock assembly in the engaged position to thereby prevent movement thereof to the locked position.
In still another exemplary embodiment, a thrust reverser lock assembly for use in a system having at least one drive mechanism for moving a thrust reverser between deployed and stowed position includes a lock assembly and a lock and a lock inhibitor assembly. The lock is selectively operable to move between a locked and an unlocked position, respectively, to thereby prevent and allow rotation of each drive mechanism, respectively. The lock inhibitor assembly is selectively operable to move between an engaged and a disengaged position, whereby the lock inhibitor engages the lock assembly in the engaged position to thereby prevent movement thereof to the locked position.
In yet still another exemplary embodiment, in a jet engine thrust reverser system including at least one actuator assembly that moves in a stow and a deploy direction and having a lock that is moveable between a locked and an unlocked position, to thereby allow and prevent movement of the actuator assembly in the deploy direction, respectively, a method of operating the actuator assembly includes moving the lock to the unlocked position. The lock is physically engaged to prevent its movement to the locked position. The actuator is moved in the deploy direction and in the stow direction. The physical engagement of the lock is removed upon the actuator reaching a substantially fully stowed position, whereby the lock automatically moves to the locked position.
Other independent features and advantages of the preferred system and actuator will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.